Yes, KERATIN is a Scrabble word!

Letter values in Scrabble US: K 5, E 1, R 1, A 1, T 1, I 1, N 1.

Is it a valid word?

KERATIN is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a fibrous scleroprotein that occurs in the outer layer of the skin and in horny tissues such as hair, feathers, nails, and hooves